I could extemporise you could extemporise she could extemporise we could extemporise you could extemporise they could extemporise
V-ing form
I could be extemporising you could be extemporising she could be extemporising we could be extemporising you could be extemporising they could be extemporising
Perfect
I could have extemporised you could have extemporised she could have extemporised we could have extemporised you could have extemporised they could have extemporised
V-ing perfect
I could have been extemporising you could have been extemporising she could have been extemporising we could have been extemporising you could have been extemporising they could have been extemporising
Negation
Simple form
I could not extemporise you could not extemporise she could not extemporise we could not extemporise you could not extemporise they could not extemporise
V-ing form
I could not be extemporising you could not be extemporising she could not be extemporising we could not be extemporising you could not be extemporising they could not be extemporising
Perfect
I could not have extemporised you could not have extemporised she could not have extemporised we could not have extemporised you could not have extemporised they could not have extemporised
V-ing perfect
I could not have been extemporising you could not have been extemporising she could not have been extemporising we could not have been extemporising you could not have been extemporising they could not have been extemporising
Interrogative form
Simple form
could I extemporise? could you extemporise? could she extemporise? could we extemporise? could you extemporise? could they extemporise?
V-ing form
could I be extemporising? could you be extemporising? could she be extemporising? could we be extemporising? could you be extemporising? could they be extemporising?
Perfect
could I have extemporised? could you have extemporised? could she have extemporised? could we have extemporised? could you have extemporised? could they have extemporised?
V-ing perfect
could I have been extemporising? could you have been extemporising? could she have been extemporising? could we have been extemporising? could you have been extemporising? could they have been extemporising?
Interro-negative form
Simple form
could I not extemporise? could you not extemporise? could she not extemporise? could we not extemporise? could you not extemporise? could they not extemporise?
V-ing form
could I not be extemporising? could you not be extemporising? could she not be extemporising? could we not be extemporising? could you not be extemporising? could they not be extemporising?
Perfect
could I not have extemporised? could you not have extemporised? could she not have extemporised? could we not have extemporised? could you not have extemporised? could they not have extemporised?
V-ing perfect
could I not have been extemporising? could you not have been extemporising? could she not have been extemporising? could we not have been extemporising? could you not have been extemporising? could they not have been extemporising?